U.S. patent number 8,012,131 [Application Number 11/623,533] was granted by the patent office on 2011-09-06 for extractable dose setting knob.
This patent grant is currently assigned to TecPharma Licensing AG. Invention is credited to Juerg Hirschel, Ulrich Moser, Christian Schrul.
United States Patent |
8,012,131 |
Moser , et al. |
September 6, 2011 |
Extractable dose setting knob
Abstract
An injection device for dispensing a dose of a substance, the
device including a housing, a dispensing element which can be
displaced relative to the housing and a locking element which can
be coupled with the dispensing element during or after a substance
dispensing operation so that after the dispensing element has
effected a dispensing operation once, it can no longer be operated
to dispense another dose, and a method of locking an injection
device after a substance has been dispensed once, whereby a
dispensing element operated to dispense the substance is locked or
blocked before, during or after dispensing a set dose so that no
more substance can be dispensed.
Inventors: |
Moser; Ulrich (Heimiswil,
CH), Schrul; Christian (Burgdorf, CH),
Hirschel; Juerg (Aarau, CH) |
Assignee: |
TecPharma Licensing AG
(Burgdorf, CH)
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Family
ID: |
38190154 |
Appl.
No.: |
11/623,533 |
Filed: |
January 16, 2007 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20080071226 A1 |
Mar 20, 2008 |
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Foreign Application Priority Data
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Jan 17, 2006 [DE] |
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10 2006 002 383 |
Feb 1, 2006 [DE] |
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10 2006 004 563 |
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Current U.S.
Class: |
604/208; 604/207;
604/224; 604/210; 604/218; 604/228; 604/187; 604/110; 604/181 |
Current CPC
Class: |
A61M
5/3156 (20130101); A61M 5/3155 (20130101); A61M
5/3158 (20130101); A61M 5/31585 (20130101); A61M
5/2448 (20130101); A61M 5/31511 (20130101); A61M
5/502 (20130101); A61M 5/31555 (20130101) |
Current International
Class: |
A61M
5/00 (20060101); A61M 5/315 (20060101) |
Field of
Search: |
;604/110,181,187,207,208,209,210,211,218,224,228,500,506 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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603401 |
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Oct 1934 |
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DE |
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1053143 |
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Mar 1959 |
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DE |
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3030239C2 |
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Feb 1982 |
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DE |
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197 30 999 |
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Dec 1998 |
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DE |
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101 63 325 |
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Feb 2003 |
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DE |
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101 60 393 |
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Jun 2003 |
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DE |
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102 32 158 |
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Feb 2004 |
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DE |
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102 48 061 |
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May 2004 |
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DE |
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10 2004 004 310 |
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Aug 2005 |
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DE |
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0 373 321 |
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Jun 1990 |
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EP |
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0713403 |
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May 1996 |
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EP |
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897 729 |
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Feb 1999 |
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EP |
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0713403 |
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Dec 1999 |
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EP |
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WO 00/62839 |
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Oct 2000 |
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WO |
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Primary Examiner: Sirmons; Kevin C
Assistant Examiner: Patel; Shefali D
Attorney, Agent or Firm: Dorsey & Whitney LLP Bruhn,
Esq.; David E.
Claims
The invention claimed is:
1. An injection device for setting and dispensing a dose of a
substance, the device comprising: a housing; a guide sleeve
arranged in the housing, the guide sleeve comprising one or more
lugs; a dispensing element which can be displaced relative to the
housing by a user pulling the dispensing element out of the housing
or the user pushing the dispensing element into the housing, the
dispensing element comprising at least one catch orifice; and a
toothed rack arranged in the housing and guided by the guide
sleeve, the toothed rack displaceable relative to the housing and
the guide sleeve and comprising an end configured to engage with a
stopper, a plurality of teeth disposed at a middle portion of the
toothed rack and a locking element arranged at an end opposite the
end configured to engage with the stopper, wherein the plurality of
teeth are configured to engage with the one or more lugs to allow
the toothed rack to move in a dispensing direction but not in a
direction opposite the dispensing direction, and the locking
element is configured to establish a coupling engagement with the
at least one catch orifice before or during a substance dispensing
operation and at least after the substance dispensing operation,
and is further configured to remain substantially unengaged with
the catch orifice until after a dose setting operation is complete;
whereby, due to an engagement between the at least one or more lugs
and the teeth and the coupling engagement between the locking
element and the catch orifice after the dispensing element has
effected the substance dispensing operation once, the device can no
longer be operated to dispense another dose.
2. The injection device as claimed in claim 1, wherein the
dispensing element is one of a knob or rotating knob by which a
dose to be dispensed can be set.
3. The injection device as claimed in claim 1, wherein the at least
one catch orifice is arranged on a face of the dispensing element
and is able to interact with the locking element to form a
retaining connection.
4. The injection device as claimed in claim 3, wherein the at least
one catch orifice comprises one of at least one cam or recess.
5. The injection device as claimed in claim 4, wherein the
retaining connection is a positive connection between the catch
orifice cam or recess and the locking element.
6. The injection device as claimed in claim 3, wherein at least two
catch orifices are associated with the dispensing element, the
catch orifices extending in a circumferential direction relative to
the dispensing element and axially offset from one another for
co-operating with the locking element.
7. The injection device as claimed in claim 6, wherein the catch
orifices are on one of an external face or internal face of the
dispensing element.
8. The injection device as claimed in claim 7, wherein the catch
orifices are recesses.
9. The injection device as claimed in claim 3, wherein at least one
of one of a web or groove is on an external face of the dispensing
element, the at least one of one of a web or groove complementing
at least one of a groove or web associated with the injection
device to form an anti-rotation lock.
10. The injection device as claimed in claim 1, wherein the
dispensing element comprises a dose setting position in which the
dispensing element is rotatable to set a selected dose, and upon
setting the dose, the dispensing element is extracted by the user
to a loading position in which the coupling engagement between the
locking element and the at least one catch orifice is
established.
11. The injection device as claimed in claim 10, wherein in the
loading position, the coupling engagement prevents the dispensing
element from rotating relative to the toothed rack.
12. The injection device as claimed in claim 10, wherein upon the
user pushing the dispensing element in the dispensing direction
into the housing, the toothed rack is carried by the dispensing
element.
13. The injection device as claimed in claim 1, wherein the
dispensing element comprises a retained position in which the
dispensing element is releasably retained by the locking element
and is prevented from rotating, and a dosing position, which is
reached by the user pulling the dispensing element out from the
housing, and in the dosing position, the dispensing element is
rotatable to select a dose.
14. The injection device as claimed in claim 13, wherein upon
selecting the dose, the dispensing element is pushed into the
housing and at least one of the at least one catch orifices engages
with the locking element to form the coupling engagement.
15. The injection device as claimed in claim 14, wherein the
dispensing element further comprises at least one of one of a web
or groove on an external face of the dispensing element, the at
least one of one of a web or groove complementing at least one of a
groove or web associated with the injection device to form an
anti-rotation lock, and upon effecting the substance dispensing
operation, the at least one groove or web and the complementing at
least one groove or web engage to form the anti-rotation lock.
16. The injection device as claimed in claim 1, wherein the locking
element comprises a radially flexing member.
17. A method of locking an injection device for dispensing a dose
of a substance after a dose has been dispensed, the method
comprising: providing an injection device comprising: a housing; a
guide sleeve arranged in the housing, the guide sleeve comprising
one or more lugs; a dispensing element which can be displaced
relative to the housing by a user pulling the dispensing element
out of the housing or the user pushing the dispensing element into
the housing, the dispensing element comprising at least one catch
orifice; and a toothed rack arranged in the housing and guided by
the guide sleeve, which can be displaced relative to the housing
and the guide sleeve, the toothed rack comprising an end configured
to engage with a stopper, a plurality of teeth disposed at a middle
portion of the toothed rack and a locking element arranged at an
end opposite the end configured to engage with the stopper, wherein
the plurality of teeth are configured to engage with the one or
more lugs to allow the toothed rack to move in a dispensing
direction but not in a direction opposite the dispensing direction,
and the locking element is configured to form a coupling engagement
with the catch orifice and to remain substantially unengaged with
the catch orifice until after a dose setting operation is complete;
and locking the dispensing element associated with the injection
device before or during dispensing a dose and at least after
dispensing the dose whereby, locking is established due to an
engagement between the at least one lug and the teeth and the
coupling engagement between the locking element and the catch
orifice after a dose has been dispensed once, and the device can no
longer be operated to dispense another dose.
18. The method according to claim 17, further comprising the step
of setting the dose using a setting element retained relative to
the injection device by one of static friction or a catch
mechanism.
19. An injection device for dispensing a dose of a substance, the
device comprising a housing, an ampoule holder displaceable
relative to the housing, a dual chamber ampoule accommodated in the
ampoule holder, a guide sleeve arranged in the housing, the guide
sleeve comprising one or more lugs, a dispensing element
displaceable relative to the housing to set a dose of substance to
be administered and to effect a dispensing operation, the
dispensing element comprising at least one catch orifice, and a
toothed rack arranged in the housing and guided by the guide
sleeve, which can be displaced relative to the housing and the
guide sleeve, the toothed rack comprising an end configured to
engage with a stopper, a plurality of teeth disposed at a middle
portion of the toothed rack and a locking element arranged at an
end opposite the end configured to engage with a stopper, the
plurality of teeth configured to engage with the one or more lugs
to allow the toothed rack to move in a dispensing direction but not
in a direction opposite the dispensing direction, the locking
element coupleable to the dispensing element before or during
dispensing a dose and at least after the dose has been dispensed in
a dispensing operation and configured to remain substantially
unengaged with the at least one catch orifice until after a dose
setting operation is complete, whereby, due to an engagement
between the at least one lug and the teeth and the coupling
engagement between the locking element and the catch orifice after
the dispensing element has effected the dispensing operation once,
the device can no longer be operated to dispense another dose, and
wherein the injection device is configured such that a first
substance and a second substance contained in the dual chamber
ampoule are admixed as the ampoule holder is displaced relative to
the housing.
20. An injection device for dispensing a dose of a substance, the
device comprising a housing, an ampoule holder displaceable
relative to the housing, a guide sleeve arranged in the housing,
the guide sleeve comprising one or more lugs, a dispensing element
displaceable relative to the housing, the dispensing element
comprising at least one catch orifice, and a toothed rack arranged
in the housing and guided by the guide sleeve, which can be
displaced relative to the housing and the guide sleeve, the toothed
rack comprising an end configured to engage with a stopper, a
plurality of teeth disposed at a middle portion of the toothed rack
and a locking element arranged at an end opposite the end
configured to engage with the stopper, the plurality of teeth
configured to engage with the one or more lugs to allow the toothed
rack to move in a dispensing direction but not in a direction
opposite the dispensing direction, wherein the locking element can
be coupled with the dispensing element before or during a substance
dispensing operation and at least after the substance dispensing
operation and is configured to remain substantially unengaged with
the catch orifice until after a dose setting operation is complete,
whereby, after the dispensing element has effected the dispensing
operation once, the device can no longer be operated to dispense
another dose, wherein in an initial state the dispensing element is
positioned relative to the housing such that the dispensing element
cannot be grasped by a user, and wherein the ampoule holder is
coupled to the dispensing element such that as the ampoule holder
is displaced relative to the housing the dispensing element is
moved proximally from the initial position to a dose setting
position.
Description
CROSS-REFERENCE TO RELATED APPLICATION(S)
This application claims priority to German Application No. DE 10
2006 002 383.8, filed on Jan. 17, 2006 and German Application No.
DE 10 2006 004 563.7, filed on Feb. 1, 2006, the contents of which
are incorporated in their entirety by reference herein.
BACKGROUND
The present invention related to devices for dispensing,
administering, injecting or delivering substances, and to methods
of making and using such devices. More particularly, it relates to
devices for dispensing a substance, such as injection devices or
injection pens, having a dose setting element for administering a
set or selected dose of an injectable product. In some embodiments,
such injection devices may be used for self-administering a
product, may be disposable, and/or may be used with a single or
dual chamber ampoule.
Relatively small, easily portable injection devices, which may be
referred to as injection pens, are commonly used as a means of
self-administering medicaments. Ease of use, accurate dose metering
and reliability of the dose setting are important factors for
self-administering medicaments, such as insulin or a hormone.
Patent specification DE 10 2004 310, owned by the owner of the
present application, discloses an injection device with a dose
metering element, which effects a forward drive movement relative
to the housing of the injection device in a forward drive direction
and a dose metering movement opposite the forward drive direction.
The dose metering element is coupled with a conveying mechanism so
that the forward drive movement causes a conveying movement of the
conveying mechanism. The length of a travel distance determining
the dose to be dispensed which the dose metering element covers
during the forward drive movement is set by the dose metering
movement. The housing constitutes a first catch mechanism in a
sleeve portion surrounding the dose metering element and a second
catch mechanism formed by the dose metering element or a separate,
additional dose metering catch body, and a catch engagement of the
catch mechanisms can be released by a dose metering movement of the
dose metering element or the separate, additional dose metering
body without any rotating motion.
Patent specification U.S. Pat. No. 5,807,346 discloses a measuring
instrument for dispensing different doses of a fluid, which has a
reservoir for accommodating the fluid, a displaceable toothed rack
element axially disposed inside and a pushing element which can be
operated by the user. Annular notches are provided on the toothed
rack element, and the housing has various axial slots distributed
across its periphery. An outwardly projecting pin is provided on
the pushing element, which is able to engage in one of the axial
slots of the housing, thereby enabling the setting element to be
easily extracted by the user.
Patent specification EP 0 713 403 B1 discloses a syringe with a
barrel, which defines or has a cylinder. The cylinder has a nozzle
at one end and encloses a plunger able to slide in the longitudinal
direction inside the cylinder. The distance by which the plunger is
able to move inside the cylinder defines the volume administered by
the syringe, and the plunger is drivingly coupled with a slide so
that it moves parallel with the plunger. The longitudinal distance
by which the plunger is able to slide inside the cylinder is
defined by restrictions to the movement caused by a stop surface on
the barrel or on the slide co-operating with end stops on the slide
or barrel. The syringe can be locked in a state in which the stop
surface and the end stops are able to move relative to one another
within movement restrictions which can be selected from one or more
selectable, pre-defined movement restrictions. Because the stop
surface has an insert which can be inserted in an orifice in the
barrel or slide so that it projects out from it and can only be
removed with great difficulty or by using a special tool, the
projecting part of the insert acts as a stop surface. The position
of each such orifice relative to the end stops defines one of the
pre-selected movement distances.
SUMMARY
An object of the present invention is to provide an injection
device which is easier to set while simultaneously reducing the
likelihood of incorrect operation.
In one embodiment, the present invention comprises an injection
device for dispensing a dose of a substance, the device comprising
a housing, a dispensing element which can be displaced relative to
the housing and a locking element which can be coupled with the
dispensing element during or after a substance dispensing operation
so that after the dispensing element has effected a dispensing
operation once, it can no longer be operated to dispense another
dose, and a method of locking an injection device after a substance
has been dispensed once, whereby a dispensing element operated to
dispense the substance is locked or blocked before, during or after
dispensing a set dose so that no more substance can be
dispensed.
Based on a first aspect of the present invention, an injection
device in accordance with the present invention has a housing
device for a substance to be dispensed, in which the substance to
be dispensed can either be introduced directly or into which it can
be inserted in a container, for example an ampoule, in which case
the housing device is designed as an ampoule holder. The housing
device can be moved relative to the injection device, whereby an
element of the injection device constituting the holder or ampoule
holder can be pushed or screwed into it or a part of it, for
example into the housing. If using a dual chamber ampoule of a
known type, the substances contained in the dual chamber ampoule
can be admixed as a result of the pushing or screwing-in operation
and, thus, may be made ready for administering to a patient. A dose
metering or setting element is also provided, for example a
rotating knob or moveable structure, for setting the dose of
substance to be administered from the injection device, and the
quantity or dose of substance to be administered can be selected or
fixed by moving the dose metering or setting element to a certain
position. In an initial state, the dose metering element is pushed
so far into the injection device that it can not be grasped or held
by a user, or can only be grasped and manipulated with great
difficulty.
For some purposes of the present invention, the housing device for
the substance to be administered, for example a screw-in or push-in
ampoule container, which can be screwed or pushed into the
injection device, is coupled with the setting element so that as
the substance housing device is being pushed into the injection
device or into a housing or once it has been completely or almost
completely pushed in, the setting element is at least partially
pushed out of the injection device or a housing so that it can be
operated by a user to set a dose. The dose metering or setting
element may be provided in the form of a rotatable dose setting
knob of a type known per se, for example, which is disposed
generally at the proximal or rear end of the injection device and
is fixedly connected to a dose metering knob sleeve, for example,
which is able to slide axially inside and/or out of the injection
device to push the dose metering knob out, thereby releasing it to
enable a dose to be set.
In one preferred embodiment, the dose metering element can be
coupled with the injection device so that it can not be rotated in
a state in which it is pushed into the injection device and/or, for
example, can not be rotated until it has been pushed out to set a
dose. The dose metering element may be designed so that when it has
been moved to a predetermined, defined position relative to the
injection device in which it can be rotated to set the dose, it can
be pulled farther out of the injection device to charge the
injection device. As the dose metering element is being pulled out
farther, it is rotationally locked and/or may also be rotatable for
example. In another option, the dose is not set until after the
dose metering element has been charged or pulled out of the
injection device and the dose metering element is not locked to
prevent rotation until it has been pushed back into the injection
device to dispense the substance.
In some embodiments, in the initial state or in the retracted
state, the setting element may be retained by static friction or by
a catch mechanism in the injection device or in a housing of the
injection device. The force of the static friction or the catch
mechanism can be overcome by pushing the substance housing device,
such as the ampoule holder to push the setting element out of the
injection device. A proximal end of the substance housing element
or a setting element-extraction element provided on it may come
into contact with the setting element or dose metering element or
may be connected to or coupled with the dose metering element by
one or more other elements, e.g. a guide sleeve, secured relative
to the injection device by a releasable catch mechanism or holder,
so that a pushing-in or turning movement of the substance housing
device causes the setting or dose metering element to be pushed
out. A catch element or some other fixing element may also be
provided, which holds the dose metering element in the state pushed
into the injection device and can be released by the substance
housing device directly or by an element coupled with it, to enable
the dose metering element to be pushed out.
In some embodiments, a plunger rod or toothed rack is provided in
the injection device so that a proximal stopper or displacement
body in the substance housing device or in an ampoule is pushed
into the injection device relative to the substance housing region,
in other words is pushed into the ampoule, during the operation of
pushing in or screwing in the substance housing device or the
ampoule. Thus, in the case of a dual chamber ampoule, admixing of
the components contained in the dual chamber ampoule is initiated
and terminated when the plunger rod or toothed rack has been
sufficiently pushed in, so that mixing takes place in a dual
chamber ampoule in readiness for administering the substance.
In some embodiments, the coupling between the substance housing
element and setting or dose metering element is designed so that
the dose metering element is not pushed out of the injection device
until the substance housing element has been completely or almost
completely introduced or pushed in to completely or almost
completely mix the substances contained in a dual chamber ampoule.
For example, the dose metering element may not be coupled with the
substance housing element until the last part of the insertion
movement, for example the last 6 mm. In some embodiments, only
after coupling, for example once the proximal end of the substance
housing element has made contact with the dose metering element, is
the dose metering element pushed out of the injection device by the
remaining insertion path of 6 mm, for example, so that the dose
metering element can be gripped by a user and rotated to set the
dose, for example, or pushed farther out to prime the pen.
In some embodiments, a marking is provided on the dose metering
element, for example on the circumferential face of the dose
metering knob or on a dose metering knob sleeve. The marks or
indicia may be printed and serve as an aid for setting a dose and
specify dose units, for example. This dose display may be printed
or applied to the dose metering element so that it is not visible
until the dose metering element has been extracted by pushing the
dose metering element so far out, for example, that the dose
display can be seen by a user. In some embodiments, the display
printed on the dose metering element may be pushed into the region
of a viewing window provided in the housing of the injection
device, for example, and thus rendered visible.
In one embodiment of the method of the present invention, i.e., the
method of preparing an injection device for dispensing a metered
dose of a substance, a metering element is pushed into or
positioned in the injection device. The metering element, which can
not then be grasped, or can be grasped only with great difficulty,
is not pushed out of the device again until a substance housing
element, for example an ampoule holder or an ampoule, is being or
has been inserted in the injection device. Only then can the
setting or dose metering element be gripped by a user and
operated.
In another embodiment, the present invention relates to an
injection device with a housing and a substance dispensing element
which can be displaced relative to the housing, so that a movement
of the dispensing element, for example a movement pushing the
dispensing element into the injection device, forces the substance
contained in the injection device out of the injection device,
causing it to be dispensed. For the purpose of this embodiment of
the invention, at least one fixing element is provided in the
injection device, which makes it impossible to dispense another
dose when a substance has already been dispensed from the injection
device once by the dispensing element. The dispensing element may
be coupled with a dose metering or setting element or they may be
combined, so that a dose can be set by a rotation of the dispensing
element. In some embodiments, this can be accomplished by pulling
on the injection device or by pulling out the dispensing element.
The substance may then be dispensed by pushing the dispensing
element in. In some preferred embodiments, the dispensing element
may also be a rotating or dose setting knob of the injection
device. Likewise, the dispensing element may also be a housing part
of the injection device which can be displaced relative to another
element or housing part of the injection device.
In some embodiments, a locking or catch element, such as a latch
cam and/or a groove for example, is provided on the dispensing
element which, together with a complementary counter-element, e.g.,
a matching groove or latch cam of the injection device of or an
ampoule, can establish a catch connection, which can not be
released or is difficult to release, during or after a dispensing
operation, once a set, once-only dose has been dispensed. The
locking element or catch element may co-operate with a plunger rod
or toothed rack of the injection device, for example, and the
counter-element may be provided in the form of a catch element
projecting into the dispensing element, for example, and disposed
on a flexible arm, for example, such as a latch cam, by which a
positive connection is established between the dispensing element
and the toothed rack or plunger rod once the substance has been
dispensed. This being the case, the dispensing element can no
longer be moved relative to the toothed rack or plunger rod.
Likewise, the dispensing element may be fixed relative to the
injection device or a housing of it, for example by means of catch
connection, during or after a dispensing operation, to prevent a
further dispensing operation. Another option would be for the
dispensing element to move in a specific direction only, for
example to move axially and/or in rotation, to apply a locking or
blocking action, so that it is no longer possible for substance to
be dispensed from the injection device, again due to the locked
direction(s) of movement.
In one embodiment of a method of dispensing a substance from an
injection device and/or locking an injection device in accordance
with the present invention, a dispensing element for triggering or
causing substance to be dispensed is fixed or locked before, during
or after a set dose of substance to be dispensed has been
dispensed, so that the dispensing element can no longer move in a
direction by which further dispensing of a substance from the
injection device can be triggered.
In accordance with some embodiments of present invention, a
quantity or dose of a substance to be dispensed, either pre-set or
set by a user, can be dispensed only once, whereby any additional
dispensing of the substance can be blocked or prevented even if
there is still a residual quantity of the substance in the
injection device. This may be particularly necessary in the case of
dual chamber ampoules containing admixed substances which can
deteriorate or degrade in terms of quality over time, possibly
posing a health risk. In this case it would not be advisable to
administer substance to a patient again.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A to 1E are plan and sectional views illustrating the
sequence by which a dose is set and substance dispensed using one
embodiment of an injection device in accordance with the present
invention;
FIGS. 2A and 2B are views of an injection device in cross-section,
before and after extracting the dose setting knob;
FIGS. 3A and 3B are cross-sections of a first embodiment of a dose
metering and dispensing mechanism in accordance with the present
invention;
FIGS. 4A and 4B are cross-sections of a second embodiment of a dose
metering and dispensing mechanism in accordance with the present
invention;
FIG. 5A is a cross-sectional view showing an embodiment of a dose
metering knob in accordance with the invention;
FIG. 5B is an opened-out view the internal face of the dose
metering knob illustrated in FIG. 5A;
FIGS. 6A to 6C illustrate how one embodiment of a dispensing
mechanism in accordance with the present invention co-operates with
one embodiment of a toothed rack; and
FIG. 6D is an exploded diagram showing the toothed rack and
dispensing mechanism of one embodiment of the present
invention.
DETAILED DESCRIPTION
FIG. 1A is a plan view in section, showing an embodiment of an
injection device in accordance with the present invention. The
device comprises an ampoule holder 1 for accommodating a substance,
into which a dual chamber ampoule 2 with two stoppers 2a and 2b
displaceably disposed in it can be inserted. The ampoule holder 1
can be displaced relative to the housing of the injection device,
which is provided in the form of a threaded sleeve 3 in the
embodiment illustrated, and can be screwed into the internal thread
3a of the threaded sleeve 3 due to an engagement by the external
thread 1a at the proximal end of the ampoule holder 1. Due to an
engagement of the annular web 3c provided on the internal face of
the threaded sleeve 3 in the circumferentially extending groove 5d
(see FIG. 2A) on the external face of a guide sleeve 5, the guide
sleeve 5 can be connected to the threaded sleeve 3. The sleeve 5
has inwardly biased catch elements 5a on its distal or forward end
which engage in matching grooves or teeth 4a of a toothed rack 4,
which is prevented from rotating by axially extending grooves and
holds the latter so that it can not move in the proximal direction.
However, the toothed rack 4 can be moved in the distal direction
relative to the guide sleeve 5, as a result of which the catch
elements 5a provided on resilient arms slide out of the grooves or
teeth 4a of the toothed rack and snap into a subsequent groove or
teeth 4a. In the embodiment illustrated, a dose metering knob is
provided at the proximal end and serves as a dispensing and dose
metering element 6, which is pushed so far into the housing or into
the threaded sleeve 3 that it cannot be practically gripped by a
user. In the position of the injection device illustrated in FIG.
1A, which might be referred to a retail position, only the ampoule
holder 1 is able to move, e.g., can be screwed into the threaded
sleeve 3, to admix the substances contained in the dual chamber
ampoule 2. However, it is still not possible to effect a setting
operation by the dose setting knob 6.
FIG. 1B shows the injection device illustrated in FIG. 1A in the
mixing position, after the ampoule holder 1 has been screwed into
the threaded sleeve 3. By pushing the ampoule 2 held by the ampoule
holder 1 in the proximal direction, the shoulder 4c placed on the
front face of the toothed rack 4 can be moved into the ampoule 2,
thereby pushing the abutting stopper 2b into the ampoule 2 so that
the ampoule 2 can be mixed. Priming may also take place at the same
time.
As illustrated in FIG. 1C, the ampoule holder 1 can be screwed into
the threaded sleeve 3 of the injection device as far as a proximal
stop surface 1b of the ampoule holder 1 projecting on the radially
outer, distal or front face of the guide sleeve 5. As the ampoule
holder 1 is screwed in further, the guide sleeve 5 is moved in
conjunction with the ampoule holder 1 in the proximal direction
relative to the threaded sleeve 3, thereby releasing the catch
connection 3c, 5d, until a stop element 5b provided on the external
face of the guide sleeve 5 has moved against a complementary stop
element 3b on the internal face of the threaded sleeve 3, limiting
the screwing movement of the ampoule holder 1 as a result. When the
guide sleeve 5 is pushed in the proximal direction, the dose
setting knob 6 mounted in the guide sleeve 5 is pushed in the
proximal direction out of the injection device so that the dose
setting knob 6 can be used to set a dose to be dispensed from the
injection device. At the same time, the annular web 3c moves into
engagement with the circumferentially extending grooves 5e (priming
position) and 5f (end position) of the guide sleeve 5 pushed past
the ampoule holder 1 lying against the guide sleeve 5.
FIG. 1D illustrates the charged injection device, whereby the dose
setting knob 6 has been extracted or extends from the injection
device until a catch element 4b projecting out from the toothed
rack 4 in the proximal direction has latched in a catch orifice 6a
provided on the internal face of the dose setting knob 6. Thus, a
pressure applied to the dose setting knob 6 enables the toothed
rack 4 latched to it to be pushed in the distal direction of the
injection device, as illustrated in FIG. 1E, to push the stoppers
2a and 2b disposed in the ampoule 2 in the distal direction as a
result and dispense the already admixed medicament out of the
ampoule 2. When the dose metering knob 6 is pushed back into the
pen or into the threaded sleeve 3, it can no longer be moved, and
can no longer be pulled out, as will be explained below. This
ensures that the injection device can be used only for a single
dispensing operation.
FIG. 2A is a perspective view, in cross-section, showing the dose
setting knob 6 when it is retracted in the initial position, which
can be extracted from the injection device by turning or pushing in
the ampoule holder 1 by means of the guide sleeve 5, thus releasing
it for a user; see FIG. 2B.
FIG. 3A is a perspective view in cross-section showing a first
embodiment of a setting and dispensing mechanism in accordance with
the present invention. In the position illustrated, the dose
setting knob 6 can be freely rotated to select a dose, and the
snapper or catch element 4b of the threaded rod 4 biased radially
outwards can run freely around the groove 6p extending
circumferentially on the proximally inner face of the dose setting
knob 6 so that the dose setting knob 6 is also held. Once a dose
has been set, for example using a marking applied to the external
circumferential face of the dose setting knob 6, the dose setting
knob 6 can be pulled out of the injection device, as illustrated in
FIG. 3B, until the catch element 4b of the threaded rod 4 biased
radially outwards is guided by a groove 6i on the internal face of
the dose setting knob 6 and latches in one of several catch
orifices 6a or 6b (with guide grooves 6i or 6j; see FIG. 5B)
provided in the interior of the dose setting knob 6. The set dose
can be dispensed by pushing the dose setting knob 6 in so that it
pushes the threaded rod 4 in the distal direction with it, relative
to the guide sleeve 5, due to the positive connection 6a, 4b. When
the catch element 4b engages in the groove 6i of the dose setting
knob 6, as illustrated in FIG. 3B, the dose setting knob can no
longer be freely rotated but is able to slide axially in the groove
6i until it latches in the catch orifice 6a. Once pushed into the
pen, the dose setting knob 6 can no longer be moved due to this
connection 4b, 6a and because of the catch connection formed by
elements 4a, 5a or the like. The catch connection 3c, 5f between
the threaded sleeve 3 and guide sleeve 5 is stronger than the catch
connection 4a, 5a between the guide sleeve 5 and toothed rack 4, so
that a pressure applied to the dose setting knob 6 causes an axial
forward movement of the toothed rack 4 relative to the guide sleeve
5.
FIG. 4A, together with FIG. 4B, illustrates another embodiment of a
setting and dispensing mechanism in accordance with the present
invention. FIG. 4A illustrates the position of the dose setting
knob 6 as releasably retained by the catch element 4b engaging in
the groove 6p so that it can not rotate due to the engagement of
one or more guide bars 5c (see FIG. 4B) on the internal face of the
guide sleeve 5 in matching grooves or notches 6o radially disposed
on the external face of the dose setting knob 6.
When the dose setting knob 6 is pulled out of the injection device,
as illustrated in FIG. 4B, the lock preventing the dose setting
knob 6 from rotating is released by pushing the notches 6o away
from the guide bars so that the catch element 4b runs through the
empty groove 6c of the dose setting knob 6 into the setting groove
6q extending circumferentially round the internal face of the dose
setting knob 6. The dose setting knob 6 can then be freely rotated
to select a dose. The dose is set, or dose selecting is enabled, by
recesses or orifices 6a, 6b, 6m, 6n disposed in the circumferential
direction on the internal face of the dose setting knob 6 and catch
points axially offset from one another, with co-operating guide
grooves 6i to 6l (see FIG. 5B) of differing axial length. When the
dose setting knob 6 is pushed in, the catch element 4b moves along
the guide groove 6i, 6j, 6k or 6l set by the rotation position of
the dose setting knob 6 until it latches at the co-operating catch
point 6a, 6b, 6m or 6n. When the dose setting knob 6 is pushed
farther in, it drives the toothed rack 4 coupled with it via the
catch connection of the catch element 4b. When the dose setting
knob 6 has been completely pushed in, the dose setting knob 6 can
no longer be moved due to the anti-rotation lock 5c, 6o and the
coupling with the toothed rack 4 which can no longer be pulled out
in the proximal direction, so that the injection device is
locked.
FIG. 5A is a perspective view showing a section through an
embodiment of a dose setting knob 6 which can be used with both of
the variants described above and others, on which different catch
orifices 6a, 6b are disposed on the internal face in the
circumferential direction and offset from one another in the axial
direction, offering a latching option in one of the catch orifices
6a 6b for the catch element 4b lying in a different respective
axial direction due to a rotated position of the dose setting knob
6. In the embodiment described with reference to FIG. 3, the
toothed rack 4 can therefore be pulled out only as far as the
rotation position and the orifices 6a, 6b, 6m, 6n of the knob 6
allow, even if the knob 6 is fully extracted. In the embodiment
described in connection with FIG. 4, on the other hand, the toothed
rack can by pushed in only so far until it latches, predetermined
by the rotation position and the orifices 6a, 6b, 6m, 6n of the
knob 6.
FIG. 5B is a diagram showing the internal contour of the dose
setting knob 6 and illustrating how different travel paths of the
toothed rack 4 can be pre-set depending on the rotation position of
the dose setting knob 6 due to grooves 6i to 6l of differing
lengths to push in the catch element 4b, thereby enabling different
doses to be dispensed. "1st" dose in FIG. 5B denotes the smallest
dose and "4th dose" the largest dose which can be dispensed with
the second embodiment.
FIG. 6A illustrates how the setting and dose metering mechanism
co-operates with the toothed rack 4 in the embodiment illustrated
in FIG. 3, and the cross-sectional view illustrated in FIG. 6A
illustrates the maximum stroke or dispensing movement possible with
the mechanism, illustrated in the form of the distance between the
catch element 4b of the toothed rack 4 and the catch orifice 6a of
the dose 4 setting knob 6 denoted by D.sub.max.
When the dose setting knob 6 is pulled out, as illustrated in FIG.
6B, the catch element 4b latches in the catch orifice 6a and the
dose setting knob 6 can no longer be rotated once latching takes
place in the extracted position, but can be pushed in as
illustrated in FIG. 6C to dispense the dose. In the pushed-in
position, the catch lugs 5a of the guide sleeve 5 prevent the
toothed rack 4 and, hence, the dose setting knob 6 coupled with the
tooth rack 4, from being pulled back out again so that the dose
metering knob 6 is secured in the position illustrated in FIG. 6C.
In this position, the injection device cannot be operated.
Instead of a catch system or catch orifice(s), such as described in
connection with FIGS. 3 to 6, it would also be possible to provide
one or more stops, complementary stops, steps, projecting elements,
webs or cams on the dose setting knob 6, for example, as a means of
setting or selecting the dose. Likewise, the grooves 6i to 6l may
be designed as blind grooves or dead-ends without adjoining
orifices.
Embodiments of the present invention, including preferred
embodiments, have been presented for the purpose of illustration
and description. They are not intended to be exhaustive or to limit
the invention to the precise forms and steps disclosed. Obvious
modifications or variations are possible in light of the above
teachings. The embodiments were chosen and described to provide the
best illustration of the principles of the invention and the
practical application thereof, and to enable one of ordinary skill
in the art to utilize the invention in various embodiments and with
various modifications as are suited to the particular use
contemplated. All such modifications and variations are within the
scope of the invention as determined by the appended claims when
interpreted in accordance with the breadth they are fairly,
legally, and equitably entitled.
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